Fire resistant veneered panel



Jam i8, 1935. J. R. FlTzP'ATRlcK 1,987,506

FIRE RESISTANT VENERED PANEL Filed Jan. 23, 195s Patented Jan. 8, 1935 ii UNITED STATES FP1-CE 4 FIRE RESSTANT VENEERED PANEL James R.Fitzpatrick, Grand Rapids, Mich., assignor, byl mesne assignments, toReconstrucgon Finance Corporation, a Federal corpora- ApplicationJanuary 23, 1933, Serial No. 653,046

3 Claims. (Cl. :Z0-91) The primary object of the present invention is inconnection with the accompanying drawing, to produce-lumber in the formof strong, light wherein: y panels faced with wood veneers, which shallbe Figure 1 is an elevation of a panel or a piece highly fire-resistantwithout `resorting to expediof lumber in the form of a panel embodyingmy 5 ents that may discolor the ne woods employed invention; Fig. 2 is asection, on an enlarged 5 as facings. scale, through the panel; and Fig.3 is a view Bulkheads and partitions employed in the susimilar to Fig.2, showing a modification. perstructure of ships should be made as lightReferring to Figs. 1 and 2 of the drawing, 1 repas possible because, forevery pound of weight resents a thick core, preferably of light maplacedabove the water line of a ship there must terial. The core may becomposed of balsa wood, 10 be a number of pounds placed below the waterof Wood fiber or of wood composition. The core line in order to make theship stable. 'I'hese extra is made up in the form of a panel of anydesired pounds may be in the form of ballast or freight. width, limitedonly by the size of the presses in Consequently, any reductionintheweight ofthe which multiple-ply lumber must be glued up,

l5 stateroom partitions in a ship means either that and of any desiredlength. Balsa wood is very 15 the ship can carry more freight, or thatthe light, and so are some of the wood ber or wood Whole weight of thevessel may be decreased very composition boards as at presentmanufactured.

much more than the reduction in weight of the Not only is a core madefrom any of these mapartitions and thus decrease the displacementterials light in weight but it has good soundand either increase thespeed or decrease the deadening and good heat-insulating properties.

power required to drive the vessel at a given Glued to the two faces ofthe core are thin speed. Furthermore, it is important that thesemultiple-ply panels which stifEen and strengthen partitions be highlyfire-resistant. Plywood posthe structure, provide the ornamental surfacesesses properties that cause it at present to be finish, and give to thecomposite panel its calargely used for partitions and bulkheads in thepacity to resist fire. In thearrangement shown, 25 superstructure ofships, even though it does not these facing panels for the core are justalike, offer the desired degree of resistance to fire. In each beingcomposed of a relatively thick memorder to make plywood'more suitablefor these ber 2 of one of the lighter and cheaper woods, purposesattempts have been made to increase such as poplar, two layers of thinwood veneer,

its 'resistivity to fire by impregnating it with and a layer of asbestospaper. One layer 3 of 30 suitable chemicals. However, such impregnationveneer is cemented or glued directly to the inner results indiscoloration ofthe facing veneers; or under face of the core member 2whereas the and, since these facing veneers are usually of other layerconstitutes the outer or facing layer.

' rare Woods selected because of their decorative The asbestos paperlayer 5 is shown as being value, impregnation with chemicals is impraclocated between the layers 2 and 3. 'Ihese rela- 35 ticable in suchcases. Furthermore, the usual tively thin facing panels are preferablybuilt up plywoods are reasonably good conductors of separately, and arethen glued or cemented to heat and sound and, therefore, do not serve asthe relatively thicker core to form the complete heat insulators orsound deadeners, both of which panel.

40 characteristics are desirable in the partitions and The OrdinarySheet aSbeStOS 01 the mill bOald 40 bulkheads forming part of a shipsuperstructure. of commerce possesses very little shear strength vViewed in one of its aspects, the present inand, if used to form theasbestos plies in my imvention may be regarded as having for its objectproved product, makes it easy for the thin facing to produce a simpleand novel panel possessing veneers to tear loose. I have found that byirnall of the characteristics desirable in the partipregnatingcommercial sheet asbestos or mill 45 'tions and bulkheads of a shipssuperstructure, board with resin, of the synthetic type, the asasdescribed above, and, consequently, a panel bestos is suiiicientlystrengthened, particularly adapted foruse wherever some or all of suchinsofar as its capacity to resist shear stresses is characteristics areuseful or desirable. concerned, to make it possible successfully to em-The various features of novelty whereby my ploy the asbestos layerseveninvery large panels. 50

invention is characterized will hereinafter be The four plies of eachfacing panel are preferpointed out with particularity in the claims;but, ably assembled and united by glue or cement in for a fullunderstanding of my invention and any usual or suitable way, and thesefacing panels of its objects and advantages, reference may be are thenglued or cemented to the core, wherehad to the following detaileddescription taken upon my improved material is ready for use. 55

The completed panel possesses great strength for its Weight; it isself-supporting and requires very little bracing even in very largesizes; and it may be set in rabbets at the top and bottom and inpilasters where joints between adjacent panels occur, in assembling thepanel in a ship or other structure. Regarding the weight of thematerial, it should be noted that the weight of the panel as a whole isnot greatly increased by the presence of the thin layers of asbestoswhereas, when it is attempted to render wood panels lire-resistant bytreatment with chemicals, a considerable increase in weight results,such increase amounting sometimes to as much as twenty-five per cent.This increase in weight is, of course, a serious objection quite asidefrom the objection that the wood may be discolored by the chemicals.Furthermore, chemically treated panels quickly dull tools that are usedin cutting into or through them; whereas my improved panels may beworked in the same way as any ordinary lumber and have no more effect onthe tools than does such ordinary lumber.

With respect to its fire-resisting properties, it will be noted that,when a flame acts upon a face of one of my improved panels, it can burnaway only the comparatively thin veneer layers 4 and 2 before strikingthe corresponding asbestos layer. The burning of this small amount ofwood cannot produce a great fire and it can easily be put out.Consequently, the danger of a serious re resulting before attention canbe attracted thereto is minimized. By actual test, one of my improvedpanels has withstood a five-inch Bunsen ame which has a temperature offrom 1500 F. to 1800* F. for ninety minutes. At the end of that time itwas found that the ilame had not penetrated the more remote layer ofasbestos and that, although the panel was charred on the side in contactwith the test flame, the remote or cool side was but slightly scorchedand a good deal of the original strength of the panel remained. Asimilar panel, excepting that it did not contain the asbestos layers,was burned completely through in fifteen minutes. It was also found thatwith the Bunsen ame directed against one face of my improved panel, theopposite face remained comparatively cool. Wood scorching temperatureswere attained only after twenty.- five minutes. This is of considerableimportance because of the protection against any objectionable riseinstemperature afforded bythe panel to anything behind it for acomparatively long time.

after a flame has reached the panel from the op posite side. A

Although the multiple-ply face panels may be glued up separately yet, inthe completed structure, the core l together with the inner layer ofeach facing panel may be regarded as the body member that is faced onboth sides with asbestos overlaid with thin wood veneer. Furthermore,While the inner thin veneer layers of the facing panels add strength tothe structure as a whole,

-their principal function to hold the facing panels flat until they canbe glued to the main core.

In some cases the asbestos layers may be placed directly under the outerthin facing layers 4, 4. Such a'construction is shown in Fig. 3. In thisform of my invention there is only a. very thin skin of wood outwardlyfrom the asbestos and therefore only an extremely small amount ofmaterial to support combustion, as long as the asbestos stands up, whenthe panel is attacked by fire.

It will thus be seen that I have produced a panel which, among otherthings, because of its thick, light core, weighs about one-half as muchas an ordinary plywood panel of the same thickness, is rugged andself-supporting, is highly re-re- Sistant, acts as a heat insulator andto deaden sound, permits natural wood facings to be employed withoutdanger of discoloration in the process of manufacturing the panel, andmay be worked by ordinary wood working tools without dulling them.

The proportions or thicknesses of the several plies relatively to eachother may, of course, be varied within wide limits. Ordinarily, inpanels having a thickness of from seven-eighths of an inch to an inchand a half, the thin veneers 3 and 4 will have a thickness of anywherefrom one forty-eighth of an inch to one twenty-eighth of an inch, whilethe heavier auxiliary core elements 2 will be from a tenth of an inch toan eighth of an inch thick. Variations in the thickness of the panel asa whole may be brought about by increasing the thickness of the maincore and, also, if desired, of the auxiliary core elements 2. In any.event, assuming that Figs. 2 and 3 of the drawing illustrate panelshaving a thickness of an inch or so, it will be seen that these figuresare drawn on a greatly enlarged scale.

While I have illustrated and described with particularity onlya singlepreferred form of my invention, with a slight modification. I do notdesire to be limited to the exact structural details thus illustratedand described; but intend to cover all forms and arrangements which comewithin the definitions of my invention constituting the appended claims.

I claim:

1. A piece of lumber composed of a thick, light core and a multiple-plypanel overlying and cemented to each broad face of the core; each suchpanel consisting of plies of wood and an interposed layer oflasbestosimpregnated with a fireresistant material for strengthening theasbestos, all cemented together.

A2. A piece of lumber composed of a thick, light core and a multiple-plypanel overlying and cemented to each broad face of the core; each suchpanel consisting of two layers of thin wood veneer, a layer of thickveneer, and a layer of asbestos impregnated with a syntheticfire-resistant resin; one of the thin veneer layers being cemented tothe thick veneer and the asbestos being interposed between andcemented-to the other thin veneer layer and the thick veneer.

3. A piece of lumber composed of a thick, light core and a multiple-plypanel overlying and cemented to each broad face of the core; each suchpanel consisting of a layer of thin wood veneer next to the core, alayer of asbestos and, overlying the asbestos, a thick layer of woodveneer and then another thin layer of wood veneer.

JAMES R. FITZPATRICK.

